Linux kernel 3.13 has been released. This release includes are nftables, the successor of iptables, a revamp of the block layer designed for high-performance SSDs, a power capping framework to cap power consumption in Intel RAPL devices, improved squashfs performance, AMD Radeon power management enabled by default and automatic AMD Radeon GPU switching, improved NUMA and hugepage performance , TCP Fast Open enabled by default, support for NFC payments, support for the High-availability Seamless Redundancy protocol, new drivers and many other small improvements. Here's the full list of changes.